Itching (pruritus as it is known to doctors) is a common reaction that can have numerous causes, and sometimes even more than one. As the treatments can be less than ideal or even ineffective, it can be debilitating to some patients. Itching can come from local trauma, as you suggest, or it can be a symptom of a systemic medical problem. Allergies are a common cause, and will often have some erythema (redness) or other notable effects at the same time as the itching, but not always.
As your fingers come into contact with many different things during the day, it would seem to be most likely that the itching stems from some irritant that your skin has come into contact with. If you can document how frequently the itching occurs and then try to trace back to which factors were present or which things you had done before the itching began, you might have some success in identifying the source of your itch.
Unfortunately, however, many sources of itching remain very difficult to identify despite intense efforts. If you itching spreads, affects other parts of your body, or is related to other medical conditions that you have, you may wish to speak to your doctor